There exists a need in the art for projection lens systems and, in particular, rear projection lens systems, that have some and preferably all of the following features:
(1) The systems can be produced at low cost so as to be suitable for use in high volume consumer projection television sets.
(2) The systems can accommodate the spectral differences in the light produced by the red, green, and blue CRTs without the cost and complexity associated with full color correction.
(3) The systems have an optical performance suitable for use with the higher bandwidth signals of digital televisions.
(4) The systems exhibit a high level of image contrast.
(5) The systems produce a bright image, e.g., the systems have infinite conjugate f/#'s that are less than or equal to 1.5 and preferably are around 1.0.
(6) The systems have a wide field of view in the direction of the screen so that the distance to the screen can be reduced, e.g., a half field of view in the direction of the screen of at least 35°.
(7) The systems are relatively insensitive to changes in temperature, e.g., changes between room temperature and operating temperature.